What happened
On July 25, 2022, an Airbus A320-214, registration N562AV, was operating a commercial passenger flight from Rionegro to Bogotá. While climbing through FL195, the aircraft experienced a significant malfunction in the No. 2 engine. The crew observed the N1 rotational speed drop from 90% to 23%, accompanied by a surge in Exhaust Gas Temperature (EGT) to 977°C.
Following the engine failure, the crew executed in-flight shutdown procedures and initially declared a PAN PAN. However, because the aircraft's Auxiliary Power Unit (APU) was inoperable due to a deferred maintenance item, the aircraft was left with only a single electrical generator. This loss of power redundancy forced the crew to upgrade the alert to a MAYDAY. The flight proceeded directly to Bogotá, landing at El Dorado International Airport approximately 28 minutes later. All 182 occupants (6 crew and 176 passengers) were unharmed, and the aircraft sustained no external damage, though the engine suffered internal destruction.
The investigation
The DIACC investigation focused on the mechanical failure of the CFM56-5B engine. A borescope inspection conducted shortly after the event revealed that all high-pressure turbine (HPT) blades were fractured or missing, with three blades specifically fractured at the root where they attach to the HPT disk.
The investigation examined the engine's maintenance history, noting that the engine had previously experienced a bird strike in 2016. Investigators also analyzed the service bulletins related to the engine type, specifically SB 72-1094, which addresses fatigue issues in HPT blades. The investigation confirmed that the engine had accumulated 17,655 cycles at the time of the event, which was above the recommended removal threshold (RRT) of 16,700 cycles.
Findings
- The primary cause of the engine malfunction was the fracture and separation of high-pressure turbine (HPT) blades, which caused severe internal damage and necessitated an in-flight shutdown.
- The failure was driven by high local stresses at the "min neck" junctions and the blade bodies, which induced material fatigue and radial crack propagation.
- The loss of electrical redundancy, caused by the simultaneous inoperability of the APU and the engine failure, necessitated the emergency landing declaration.